Monday, March 12, 2007

I've been travelling this past weekend so my development efforts were on hiatus. I plan to share some more nation-wide outputs tomorrow, but I wanted to share a fantastic website that someone passed along to me for Census data. The National Historical Geographic Information System (NHGIS) website is an extremely powerful data source for Census data. The website describes it self as follows:

The National Historical Geographic Information System (NHGIS) is a projectto create and freely disseminate a database incorporating all availableaggregate census information for the United States between 1790 and 2000.

The website is made by the Minnesota Population Center at the University of Minnesota. One of the most helpful aspects of the site is that it is slightly more intuitive and more powerful than the Census' FactFinder. For example, when looking at data at the County Subdivision level, you can download data for all of the states at once - on FactFinder it seems that the only way to get the data for all 50 states is to download each one individually which is a lot of wasted work. If I am missing this facility on FactFinder - please let me know!

The other aspect of the NHGIS website is that it seems built to provide the data in time series - something that the FactFinder website doesn't really provide. The Census website is admirably powerful, but lacks a couple of features that would make it much more so.

Just to keep up with the screenshots - I've got one more to share. One of the nifty things you can do with Google Maps (the website as opposed to the desktop app Google Earth) is displays KML files. In the screenshot below I simply put the KML file I had been displaying in Google Earth on a public HTTP site and loaded up the URL in the search box on Google Maps. My KML file had a bit too much data, so Google Maps can't draw all of the polygons, but with the right parsing down of data, this would be a very effective way to share KML files with a broad audience. In fact, this is a bit of a cleaner interface than Google Earth desktop app. I think you loose the 3D, but the you do get transparency and good colors: